The goal of this research is to develop and test a method to guide repair and regeneration of the central nervous system following injury or degeneration. We propose that by creating both a regenerative environment as well as directing intrinsic plasticity among neurons, we can achieve a new milestone in neural repair. If successful, this approach could be used to treat patients suffering from central nervous system damage such as traumatic brain injury, stroke, or spinal cord injury in order to reduce the burden of neurological disease on individuals and society. Our studies employ a novel combination of targeted electrical microstimulation and stem cell therapies to guide the formation of appropriate and functional connections bypassing an injury. We will test our approach in a rodent model of incomplete cervical spinal cord injury that is representative of insults throughout the central nervous system. It is known that during development of the nervous system, stem cells produce immature astrocytes that create an environment to support axon guidance and synaptic plasticity. Here, we hypothesize that neural plasticity and the repair of damaged neurons can be facilitated by re-creating the developmental phenotype of astrocytes surrounding an injury site. In a first of its kind approach, we will derive immature astrocytes from autologous adult stem cells and transplant them near a spinal cord lesion to create a supportive environment for plasticity and neural repair. We propose that providing environmental support alone has had limited success because it does not address the intrinsic drive of neurons to grow. Synchronous and appropriate neural activity is also needed to direct the formation of functional synaptic connections in the intact and injured nervous system. Here we will use a neuroprosthetic device to deliver microstimulation to targeted sites within the spinal cord below the injury that is synchronized with functionally related activity in the motor cortex. Targeted microstimulation will strengthen appropriate and functional connections via mechanisms of Hebbian plasticity. Rather than attempt long-tract regeneration in the spinal cord, our approach aims to promote the formation of indirect connections via spared pathways bypassing the lesion. The extent of recovery will be measured using behavioral tasks, and electrophysiological and histological methods. This will determine the ability of synchronous, targeted microstimulation to guide implanted stem cells in the formation of appropriate and functional connections following damage to the central nervous system. We contend that microstimulation will collaborate with the transplant environment to produce a multiplicative effect on local plasticity.